Ore no Imōto ga Konna ni Kawaii Wake ga Nai (My Little Sister Can't Be This Cute) or Oreimo for short is a slice of life comedy about the life of Kyosuke and his new found relationship with his sister.

At first glance at the title and the events that start off in the first episode, you might think this is a dirty incest show, but it's actually very clean and not what you might think it's about.

Kyosuke and his sister Kirino never got along, but then after he finds a stray DVD case lying around and discovers it's an eroge (porn game) he is curious whose this belongs to. He discovers that his sister is the owner of the game and she later confesses about her obsession with Anime. She shows him her secret extensive collection of Anime DVD's toys, and games. He finds it awkward that she has a think for eroge featuring little sisters, but she denies any sort of perverse feelings towards her brother and only likes the games for their cuteness. She is scared of being open about her Anime obsession because she is a part-time model, grade A student, and is very popular and she is afraid of being lumped in with otaku.

Kyosuke later convinces Kirino to join an Anime community online and then talks her into going to a meetup party so she can hopefully make friends with fellow fanatics. This is where she and Kyosuke become friends with Saori and Kuroneko. Most of the antics in the show is the relationship between the 4 of them.

At times it also develops into a romantic comedy with Kyosuke between him and his childhood friend Manami and some of Kirino's friends.